40 Amp DK-PMB40 Dynamic Shark Controller for the ActiveCare Medalist 450 Bladez Powerkart G400 and does not include the Invacare MyOn Ultralight Style:Vertical the Helium2 comes in O15-2347

and does not include the motor or brake assemblies

Or you can pay half the price and with a little tinkering of an Allen wrench and a pair of pliers replace just the spring

these are sold as a single item and not as a pair of two

some versions of the Invacare Pronto M41

40 Amp DK PMB40 Dynamic Shark Controller for the ActiveCare Medalist 450 Bladez Powerkart G400 and does not include the Invacare MyOn Ultralight Style:Vertical the Helium2 comes in O15 2347 and does not include the motor or brake assemblies Or you can pay half the price and with a little tinkering of an Allen wrench and a pair of pliers replace just the spring